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  • Compound eye  (5)
  • Electron microscopy  (3)
  • House fly  (3)
  • Scopolamine  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 62 (1979), S. 193-200 
    ISSN: 1432-2072
    Keywords: Rotational behavior ; Hallucinogens ; Serotonergic-dopaminergic interactions ; LSD ; Mescaline ; Methysergide ; Cyproheptadine ; p-Chlorophenylalanine ; Amphetamine ; Scopolamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract LSD, mescaline, and MDMT (5-methoxy-N,N-dimethyltryptamine) in normal rats induced dose-dependent rotation (circling behavior), which was consistent in direction from week to week (1 week separating hallucinogen administration). The direction of LSD-induced rotation for individual animals was the same as amphetamine-induced, but not apomorphine-induced, rotation. Of the three postsynaptic serotonin antagonists (methysergide, cyproheptadine, and 2-bromo-LSD) tested, only methysergide induced rotation; this rotation was consistent in direction from week to week, and was in the same direction as LSD-induced rotation. l-LSD induced weak rotation and was approximately six times less potent than d-LSD. p-Chlorophenylalanine pretreatment increased the sensitivity to LSD, whereas α-methyl-p-tyrosine pretreatment blocked LSD-induced rotation. Simultaneous administration of LSD and amphetamine induced rotation significantly greater than amphetamine alone; a similar effect was observed with LSD plus scopolamine. However, apomorphine plus LSD induced rotation similar in magnitude to apomorphine alone. These results suggest that the mechanism by which hallucinogens induce rotation is consistent with an inhibitory action on the serotonin-containing midbrain raphe neurons. The inhibition of raphe neuronal firing could disinhibit nigrostriatal activity (possibly at the level of the substantia nigra). Methysergide-induced rotation could result from partial antagonism of postsynaptic serotonin receptors in the substantia nigra or striatum. The dopaminergic properties of LSD may attenuate rotation resulting from disinhibition of nigrostriatal activity by interacting with presynaptic nigrostriatal dopamine autoreceptors.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Rotation ; d-Amphetamine ; Apomorphine ; Scopolamine ; L-Dopa ; Haloperidol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Normal unoperated rats were tested for rotation (i.e., circling behavior) in a spherical “rotometer” and dose-response relationships were generated using d-amphetamine, apomorphine, L-Dopa, haloperidol, and scopolamine. The rotation induced by amphetamine was significantly antagonized by alphamethyl-p-tyrosine and haloperidol, but not by diethyl-dithiocarbamate. The rotation elicited by apomorphine was unaffected by alpha-methyl-p-tyrosine. Rotation was not necessarily in the same direction with high and low doses of amphetamine, or amphetamine and apomorphine administered a week apart from each other. Dopaminergic-cholinergic interactions were evident, since pilocarpine antagonized amphetamine-induced rotation whereas scopolamine did not; scopolamine elicited rotation in the same direction as that induced by amphetamine. Left and right striatal dopamine and tel-diencephalic norepinephrine levels were determined in rats injected with various doses of amphetamine and tested for rotation. There were significant bilateral differences in striatal dopamine which were related to the direction of rotation. Since amphetamine was found to be equally distributed to the two sides of the brain, the difference in striatal dopamine appeared to be the neurochemical substrate for rotation in normal rats. These results suggest that normal rats have asymmetrical levels of striatal dopamine as well as an asymmetrical complement of striatal dopamine receptors.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 16 (1969), S. 147-155 
    ISSN: 1432-2072
    Keywords: Amphetamine ; Chlorpromazine ; Scopolamine ; Drug Interactions ; Delayed Matching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two drug combinations, amphetamine-chlorpromazine and amphetamine-scopolamine, were examined in monkeys performing on a delayed matching test. Antagonism between the effects of amphetamine and chlorpromazine on both response rate and accuracy measures of performance was found. Amphetamine and scopolamine had antagonistic effects on response rate but synergistic effects on accuracy.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 149 (1974), S. 21-41 
    ISSN: 1432-0878
    Keywords: Compound eye ; Musca domestica ; Ommatidia ; Optic cartridge ; Basement membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The compound eye of the housefly, from lens to first optic neuropile (lamina ganglionaris) was examined with a scanning electron microscope. Key findings are as follows: The pseudocone cavity is enclosed by six corneal pigment cells. The nuclei of the six cells are firmly anchored to the underside of the lens and portions remain after lens delamination from the pseudocone cavity. An eccentrically-positioned, short photoreceptor cell was observed near the region where the inferior central cell initiates its rhabdom. This eminence may represent that cell's soma. The basement membrane is revealed as a two-tiered, fibrous layer with ovoid fenestrations. Each opening is sealed with a diaphragm perforated by eight retinular axons and a trachea. Conjoined distal surfaces of the satellite glial cells form a membrane-like barrier immediately underlying the basement membrane. Monopolar somata from the lamina are covered with glial cells which possibly make more intimate contact with the somata through miniscule projections. Optic cartridges with monopolar interneurons were noted. Spherical to slightly biconcave processes of these interneurons contact retinular axons. Very fine (1000 Å) filaments interweave among and contact lateral processes. Further implications are discussed as they relate to observed structures.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0878
    Keywords: OsO4 ; Cholesterol ; Symbiotes ; Aphids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the pea-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 198 (1979), S. 501-520 
    ISSN: 1432-0878
    Keywords: Peripheral retina ; Transmission electron microscopy ; House fly ; Membrane specializations and pigment cells ; Photoreceptor cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Membrane specializations of the peripheral retina of the housefly (Musca domestica) are revealed in thin sections and freeze fracture/etch replicas. Septate junctions are abundant in corner areas of the pseudocone enclosure bonding: between homologous corneal pigment cells (CPC); between homologous large pigment cells (LPC); between CPC-LPC; between Semper cells (SC); between SC-CPC. Spot desmosomes are present between Semper cells. It is likely that septate junctions function as strengthening adhesions in this area. A new membrane specialization similar to a continuous junction was observed between retinular cells of the same or adjacent ommatidium. This junction has indistinct septa in the 115Å intermembrane cleft and is intermittent in character. When this junction is absent, the apposed cells gape apart. In freeze fracture studies, this junction is characterized by bridges composed of fused membrane particles and randomly arranged particles on the P face, and non-corresponding grooves on the E face. The ridges are elongate and roughly parallel and sometimes they form enclosures. Mitochondria line up along these junctions, often within 90Å of the unit membrane. This membrane specialization has characteristics of tight and continuous junctions. In line with previous findings, we suggest that this junction assists in retinular cell orientation, possibly in enforcing the ommatidial twist and in maintaining localized ionic concentration gradients between retinular cells.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 170 (1976), S. 77-88 
    ISSN: 1432-0878
    Keywords: Compound eye ; House fly ; Large pigment cells ; Corneal pigment cells ; High voltage and conventional electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure and cellular associations of the large pigment cells (LPC's) of the compound eye of the house fly were studied with high voltage and conventional electron microscopy. Depending on the sector of the compound eye, the facets are either rectangular or hexagonal. The underside of each facet has indentations exactly aligned with those on top into which inserts an angulated sleeve of LPC's. Under the rectangular lens facet 6 or 8 small compact (in cross section) LPC's join four elongate LPC's. Clusters of compact cells alternate in this ring with elongate ones. Compact cells compress together and become quadrangular (in cross section) several microns below their insertion into the lens and form “building block” corners while elongate cells form “side rails” for the rectangular type of distal pseudocone enclosure. Beneath hexagonal facets all LPC's are rather elongate with out corner cells. In both facet types LPC's enclose the pseudocone for a longitudinal distance of 4 μm and then are displaced as bordering cells by a sleeve of two corneal pigment cells (CPC's), each of which encloses half of the proximal pseudocone. For the following 6 μm of longitudinal distance these concentric sleeves of CPC's and LPC's form a double layer around the pseudocone. At about 10 μm below lens base the two sleeves separate; LPC's become attenuated and extend cable-like to the basement membrane and CPC's enclose the proximal pseudocone, Semper cells and distal retinula. The junction between lens and LPC's has critical structural value in that (1) this is the sole anchorage to the lens by the lengthy remainder of the ommatidium, and (2) LPC's enclose the semiliquid pseudocone in the most distal portion of the pseudocone. In addition to vertical support, the LPC's send out numerous lateral processes that make structural contact among themselves, with the corneal pigment cells and the photoreceptor cells. The structural features of this array are discussed relative to possible physiological roles.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 148 (1974), S. 287-300 
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Antibiotics ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of penicillin and chlortetracyline HCl on the fine structure of the intracellular symbiotes of the pea aphid were studied in an attempt to remove the symbiote population. High penicillin concentrations, 1% and 0.1%, caused symbiote breakdown but were toxic and/or repellent to the aphids; at 0.1% specific effects were observed on the symbiotes' cell walls. After the use of 0.01% penicillin in the aphid diet, the symbiotes had abnormal cell walls and were abnormally dilated; however, symbiote division and transmission from one aphid generation to the next seemed unaffected and the aphids appeared normal. Aphids fed 0.1% chlortetracycline failed to reproduce. After 7 days, their symbiotes were found to break down at a high rate but aphid mitochondria were also adversely affected at this stage. Following 0.002% chlortetracycline, the aphids produced aposymbiotic progeny with apparently normal mitochondrial populations; these larvae failed to develop.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 167 (1976), S. 537-545 
    ISSN: 1432-0878
    Keywords: House fly ; Retinular axons ; Interneurons ; Lamina ganglionaris ; High voltage electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic cartridges of the first optic neuropile (lamina ganglionaris) of the housefly were examined by high voltage electron microscopy (HVEM). Stereo pairs (from thick, i.e., 0.25 μm, sections viewed at 1,000 kV) provided a three dimensional representation of cartridge neurons and clearly revealed the lateral spread, bifurcation and some functional associations of Type I (L1, L2) monopolar interneurons. Slightly proximal to cartridge neck level, pairs of retinular (R) axons made contact with each other and it appeared that R processes projected through the cleft between the Type I interneurons. No junctional modifications were seen between contiguous R axon terminals. The speculation was made that functional contact might exist between neighboring R axons prior to their extensive synapses with principal first order interneurons. Such alleged coupling between R axons would account for several electrophysiological findings from other laboratories. Modifications in EM technique applicable for HVEM were detailed. The value of obtaining thick serial sections and the use of the HVEM in expediting three dimensional reconstructions of neuropile were demonstrated.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 159 (1975), S. 351-367 
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Vesicles ; Organelles ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. The most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). The vesicles appear to form by a budding process at the outer cell wall layer. Subsequently, the vesicles, we suggest, may move out into the mycetocyte cytoplasm via a similar budding of the membrane envelope. The Golgi apparatus was found to be an important structural component of the primary mycetocyte; it is continuous with the rough endoplasmic reticulum and the latter, in turn, appears to be closely connected to the primary symbiote membrane envelope. This may be of functional significance. A number of other organelles not previously described in mycetocytes were found, including transparent vacuoles, granular bodies, multivesicular bodies and microfilaments. The chemical composition of the various vesicles and organelles is unknown at present.
    Type of Medium: Electronic Resource
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